Using a Block-Processing Discriminator for Precise Tracking of Starlink Signals
Christian A. Lichtenberger, Florian P. C. Binder, Ottavio M. Picchi, Francesco Menzione, Thomas Pany · Proceedings of the Satellite Division's International Technical Meeting (Online)/Proceedings of the Satellite Division's International Technical Meeting (CD-ROM) · 2025
Signals of opportunity (SoOP) from low earth orbit (LEO) constellations such as Starlink are emerging as a promising complement or alternative to traditional global navigation satellite system (GNSS), offering stronger signals, larger bandwidths, and enhanced resilience to interference. This paper introduces a novel block-processing discriminator to be used within a GNSS tracking channel to provide stability even for discontinous broadcast of the signal. It keeps the signal reliably in lock by coherently accumulating multi-correlator outputs across consecutive frames. Implemented within the Multi-Sensor Navigation Analysis Tool (MuSNAT) software-defined radio (SDR) framework, the proposed method enables robust and precise code and frequency tracking of Starlink orthogonal frequency-division multiplexing (OFDM) signals, even when the replica is sparse using only primary synchronization sequence (PSS)/secondary synchronization sequence (SSS). Real-world experiments using Ku-band downlink recordings demonstrate that the approach achieves discriminator noise levels close to theoretical bounds and produces high-quality Doppler and code rate observables, even under suboptimal conditions. Compared with standard GNSS-like discriminators, the block-processing discriminator maintains lock more reliably and supports the derivation of precise navigation observables. These results highlight the potential of the technique to significantly enhance LEO-positioning, navigation and timing (PNT) performance and pave the way for hybrid positioning systems that integrate LEO constellations with GNSS.